Maximum Yield USA April 2017 | Page 52

“ While it ’ s nice to know the PPF of a lighting system , PPF alone is often useless information to a grower .
horticultural LED lighting
Spectral distribution will have significant implications on the growth and development of plants , along with the overall energy efficiency of a lighting system . However , the amount of PAR delivered to a crop is an equally ( if not more ) important metric to focus on . Photosynthetic photon flux ( PPF ) and photosynthetic photon flux density ( PPFD ) are two metrics used to measure the amount of PAR .

“ While it ’ s nice to know the PPF of a lighting system , PPF alone is often useless information to a grower .

Photosynthetic Photon Flux
This measures the total amount of PAR that is produced by a lighting system each second . This measurement is best taken using a specialized instrument called an integrating sphere , which captures and measures essentially all photons emitted by a lighting system . The unit used to express PPF is micromoles per second ( μmol / s ).
Fig . 2 : Spectral distribution chart of an HPS lighting system .
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